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2.7 Monitoring Equipment
According to the importance of the pumping system, it could be useful to maintain a strict control
of the performances and conditions of the process. The use of instruments to monitor the pressure
of the suction and discharge circuit is recommended.
The installation of a proper pressure gauge on both the suction and discharge piping is
recommended. The installation of gauges allows an easy control of the correct
functioning of the pump in relation with the required working point. In case of cavitation
or other dysfunctions, the gauges will show evident pressure fluctuations.
2.7.1 Control of Pump In Explosive Atmosphere Zones ATEX ZONE 2
In addition to the general warnings stated in this manual, special pumps used in potentially
explosive areas have to be installed with control equipment specified in this paragraph to maintain
a strict monitoring of the performances and process conditions. The control equipment mounted
near the pump has to be certified for the same hazardous zone as the pump installed unless it’s
protected by an airtight closure cabinet also certified.
The installation of pumps type EM-(C-T-P) for use in potentially explosive areas has to follow the
rules stated in the ATEX 2014/34/EU Directive.
In particular the requirements referred to the manufacturer applicable to apparatus of Category
3 of group II (explosive atmosphere due to gas, vapours or mists presence) are the following:
• The devices have to be designed and manufactured so that they avoid trigger sources
predictable during normal functioning.
• During expected functioning conditions, the surface temperatures must not exceed the
maximum design temperatures indicated in paragraph 3.1. An eventual overcoming is
endurable, in exceptional cases, if the manufacturer adopts extra special protections.
Even the monitoring of the electric power absorbed by the motor is possible using a
wattmeter.
If the temperature of the pumped liquid represents a critical element install in the system
a thermometer, preferably on suction line.
These control instruments can advise of abnormal operating conditions of pumps such
as: accidentally closed valves, missing liquid, overloads etc.